Drill Hole Spacing Analysis for Evaluation of Quartz Sand Resources as Residual Material from On-Land Alluvial Tin Processing based on Global Estimation Variance and Kriging Variance, with Case Study in the Bangka and Belitung Islands, Indonesia. J. Eng. Technol. Sci. [Internet]. 2024 Sep. 30 [cited 2026 Sep. 30];56(5):652-65. Available from: https://jets.itb.ac.id/jets/article/view/446